1. Field of the Invention
The invention relates to an automatic baking apparatus, more particularly to a hot-air circulation unit and a shaking blade of the baking apparatus.
2. Description of the Related Art
According to U.S. Pat. No. 4,903,587, an automatic baking apparatus includes a surrounding wall that defines a heating chamber therein, a kneading case mounted centrally in the heating chamber, a hot-air circulation unit for supplying hot air into the heating chamber, a shaking blade mounted rotatably within the kneading case and rotatable about a vertical axis, a motor for driving the shaking blade, and a microcomputer having means for controlling operation time of the motor and the hot-air circulation unit to vary duration of kneading, fermentation, baking and cooling steps. The microcomputer is effective to complete baking process with uniform product quality within a constant length of time.
Some of the drawbacks resulting from the use of the aforementioned baking apparatus are as follows:
(I) The hot-air circulation unit includes a lower heater installed below the kneading case at one side of the heating chamber. During circulation of hot air within the heating chamber, the flow speed of hot air decreases upon reaching a corner of the heating chamber located under the kneading case opposite the lower heater. This slowdown retards the succeeding hot air so as to lower the baking ability of dough in the kneading case.
(II) In the aforementioned baking apparatus, the shaking blade is shaped as an elongated vertical plate with uniform width so that the blade has a large kneading face to strike the dough. A high-power motor is thus required to drive the blade in order to knead the dough.